Effect of Endovascular Treatment Rate on Population Level Outcomes and Survival After Intact Abdominal Aortic Aneurysm Repair

Abstract

The aim was to study outcomes of endovascular aneurysm repair (EVAR) and open surgical repair (OSR) of abdominal aortic aneurysms (AAAs) in four geographically adjacent populations with identical demographics and variable EVAR rates. This was a multicentre cohort study based on local and national registry data from an area of 815000 inhabitants. The study involved 527 consecutive patients with an intact AAA treated with EVAR (n=327) or OSR (n=200) between 2010 and 2016. The catchment area was divided into four health care districts (populations A, B, C, and D) with one central hospital in each district. Each hospital decided independently between OSR and EVAR for patients within their population; OSR was performed in all hospitals while EVAR was centralised in one of them. Patient demographics and treatment outcomes were extracted from local registries. Population demographics, overall AAA incidence, and mortality data were retrieved from a national database. The rate of new intact AAA diagnosis varied between 20 and 29 per 100000 inhabitants/year with the highest incidence in population D (p<.001). The intact AAA repair rates were 9.8, 8.9, 9.9, and 8.7 per 100000 inhabitants/year for populations A, B, C, and D, respectively (p=.64). There were no significant differences in mean age (73.6±8.0 years) or mean aortic diameter (62±13mm) between the treated patient populations. Groups A and B had high EVAR rates (74% and 72%, respectively) whereas the EVAR rates were lower in groups C and D (50% and 38%, respectively) (p<.001). The 30 day mortality rates were 2%, 2%, 4%, and 1% (p=.55), and complication rates were 17%, 12%, 15%, and 11% (p=.39) for A, B, C and D, respectively. There were no significant differences in mortality, complication or re-intervention rates between the groups during the mean follow up of 3.3±2.0 years. At population level, high EVAR rates had no measurable effect compared with lower EVAR rates on the outcomes in patients with intact AAA.